Identification of 22 N-glycosites on spike glycoprotein of SARS-CoV-2 and accessible surface glycopeptide motifs: Implications for vaccination and antibody therapeutics
Identification of 22 N-glycosites on spike glycoprotein of SARS-CoV-2 and accessible surface glycopeptide motifs: Implications for vaccination and antibody therapeutics
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SARS-CoV-2 刺突糖蛋白上 22 个 N-糖基化位点和可及表面糖肽基序的鉴定：对疫苗接种和抗体治疗的影响
DOI：
10.1093/glycob/cwaa052
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发表时间：
2021-01-01
期刊：
影响因子：
4.3
通讯作者：
Zhang, Wen
中科院分区：
文献类型：
--
作者：
Zhou, Dapeng;Tian, Xiaoxu;Zhang, Wen
冠状病毒劫持人类酶，在其刺突糖蛋白上组装糖衣。人类抗体识别糖衣隐藏的抗原病毒肽表位的机制尚不清楚。昆虫细胞的糖基化与人类细胞产生的天然形式不同，但昆虫细胞衍生的流感疫苗已获得美国食品和药物管理局的批准。在本研究中，我们通过胰蛋白酶和胰凝乳蛋白酶消化并随后进行质谱分析，分析了 BTI-Tn-5B1-4 昆虫细胞分泌的重组严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 刺突蛋白。我们获得了所有 22 个预测 N-糖基化位点的糖肽的串联质谱 (MS/MS) 谱。我们根据低温电子显微镜和同源模型结构以及与 SARS-CoV-1 结合的可用抗体进一步分析了刺突蛋白的表面可及性。 SARS-CoV-2 的所有 22 个 N-糖基化位点均被高甘露糖 N-聚糖修饰。 MS/MS 碎片清楚地确定了糖肽的身份。聚糖的电子密度覆盖了 SARS-CoV-2 的大部分刺突受体结合域（YQAGSTPCNGVEGFNCYFPLQSYGFQPTNGVGYQ 除外），类似于 SARS-CoV-1 中的 FSPDGKPCTPPALNCYWPLNDYGFYTTTGIGYQ 区域。其他表面暴露结构域包括位于中心螺旋、连接区、七肽重复序列和 N 末端结构域上的结构域。由于大多数抗体互补位与带或不带糖修饰的肽部分结合，因此我们提出了预测互补位的蛇捕获模型：首先用互补位夹住最小长度的肽，并且靠近肽的糖修饰增强或不阻碍结合。
Coronaviruses hijack human enzymes to assemble the sugar coat on their spike glycoproteins. The mechanisms by which human antibodies may recognize the antigenic viral peptide epitopes hidden by the sugar coat are unknown. Glycosylation by insect cells differs from the native form produced in human cells, but insect cell-derived influenza vaccines have been approved by the US Food and Drug Administration. In this study, we analyzed recombinant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein secreted from BTI-Tn-5B1-4 insect cells, by trypsin and chymotrypsin digestion followed by mass spectrometry analysis. We acquired tandem mass spectrometry (MS/MS) spectrums for glycopeptides of all 22 predicted N-glycosylated sites. We further analyzed the surface accessibility of spike proteins according to cryogenic electron microscopy and homolog-modeled structures and available antibodies that bind to SARS-CoV-1. All 22 N-glycosylated sites of SARS-CoV-2 are modified by high-mannose N-glycans. MS/MS fragmentation clearly established the glycopeptide identities. Electron densities of glycans cover most of the spike receptor-binding domain of SARS-CoV-2, except YQAGSTPCNGVEGFNCYFPLQSYGFQPTNGVGYQ, similar to a region FSPDGKPCTPPALNCYWPLNDYGFYTTTGIGYQ in SARS-CoV-1. Other surfaceexposed domains include those located on central helix, connecting region, heptad repeats and N-terminal domain. Because the majority of antibody paratopes bind to the peptide portion with or without sugar modification, we propose a snake-catching model for predicted paratopes: a minimal length of peptide is first clamped by a paratope and sugar modifications close to the peptide either strengthen or do not hinder the binding.